A Compact Wideband Tunable Phase Shifter Based on Signal-Interaction Techniques

This article introduces a compact tunable phase shifter consisting of two T-shaped structures based on transversal signal-interaction concepts to achieve wide operating bandwidth. The analysis indicates that a large phase shift range, a low maximum in-band phase shift range fluctuation, and a small size can be achieved through selecting a reasonable transmission line characteristic impedance and electrical length. According to the measured results of experiments, the maximum phase shift range and fluctuation in the operating bandwidth of 1 GHz is 241
^○
and 8.2
^○
respectively. Moreover, the insertion loss at the center frequency of 3.3 GHz varies from 1.2 to 2.98 dB, and the circuit size is 0.18λ
g
×0.22λ
g
.